Patent GB-651315-A (GB)
Title: Improvements in and relating to processes for the polymerisation of ethylenically unsaturated compounds
IPC: C08F4/04
Filed: 1948-06-25
Abstract: Polymers or copolymers of an ethylenically unsaturated organic compound are made by polymerizing in the presence of a carbamylazo compound, e.g. one containing the group H2N.CO.N=N-. Preferred compounds have the formula H2N.CO.N=N.CA.R.R1, where A is a nitrile or carbamyl or carbalkoxy group in which the alkyl group contains from one to six carbon atoms and R and R1 are aliphatic, cycloaliphatic or aromatic radicals, or radicals which together form a cycloaliphatic ring.  Specified monomers are ethylene, isobutylene, styrene, butadiene; vinyl chloride, vinyl fluoride, vinyl acetate, vinyl propionate, vinylidene chloride and fluoride; vinyl butyl ether, methyl vinyl ketone; acrylonitrile, methyl methacrylate, methacrylamide; tetrafluorethylene, trifluorochloroethylene 1,1-difluoro-2,2-dichloroethylene; monovinylacetylene; tetraethylene glycol dimethacrylate, diallyl diglycollate, diallyl carbonate, diallyl phthalate, ethylene bis-(allyl maleate); chloroprene and fluoroprene and esters and anhydrides of maleic and fumaric acid. Specified carbamylazo compounds are alpha-(carbamylazo)-isobutyramide, methyl alpha - (carbamylazo) - isobutyrate, n-hexyl alpha-(carbamylazo)-isobutyrate, alpha-(carbamylazo) - alpha - methylenanthronitrile, alpha - (carbamylazo) - alpha - phenylpropionitrile; alpha - (carbamylazo) - alpha, cyclopropylpropionitrile; alpha - (carbamylazo) - cyclohexanecarbonitrile, alpha - (carbamylazo) - alpha, gamma - dimethylvaleramide, methyl alpha - (carbamylazo) - alpha, gamma-dimethylvalerate, alpha - (carbamylazo) - alpha, alpha1 - dicylohexylacetonitrile.  The polymerization may be effected in bulk, or solution, e.g. in water, tertiary butyl alcohol, benzene, cyclohexane or using granular or emulsion techniques.  High pressure and increased temperature may be used. Polyvinyl alcohol may be prepared from polyvinyl acetate produced by the process by alkaline methanolysis.  Specifications 622,374, 623,472, 626,155, 631,225, 634,757, 641,679 and 649,934, are referred to.ALSO:Compounds containing a carbamylazo group, i.e H2N.CON=N- and preferably conforming to the general formula H2N.CON=N.CA.RR1, where A is a nitrile or carbamyl or carbalkoxy group in which the alkyl group contains from one to six carbon atoms and R and R1 are aliphatic, cycloaliphatic or aromatic radicals are suitable for use as polymerization catalysts.  The compounds may be made by adding hydrogen cyanide to the semicarbazone of a ketone, and oxidizing the resulting nitrile with potassium permanganate.  Following this procedure alpha-(carbamylazo) isobutyronitrile is made from acetone, alpha-(carbamylazo)-alpha-cyclopropylpropionitrile M.P. 61-63 DEG  C. from methyl cyclopropyl ketone, alpha-(carbamylazo)-alpha, gamma-dimethylvaleronitrile M.P. 42 DEG  to 46 DEG  C. from methyl isobutyl ketone and carbamyloazo - 1 - cyclohexanecarbonitrile M.P. 135 DEG  C. from cyclohexanone.  If desired, the nitrile groups of the carbamylazonitriles may be converted to carbalkoxy groups by reacting with alcoholic hydrogen chloride followed by mild hydrolysis and the carbalkoxy groups converted to amide groups by reaction with ammonia.  Other specified carbamylazo compounds are alpha-(carbamylazo)-isobutyramide, methyl alpha - (carbamylazo) - isobutyrate, n-hexyl alpha-(carbamylazo)-isobutyrate, alpha-(carbamylazo) - alpha - methyleneanthronitrile, alpha - (carbamylazo) - alpha - phenylpropionitrile; alpha - (carbamylazo) - alpha, gamma - dimethylvaleramide, methyl alpha-(carbamylazo) - alpha, gamma dimethylvalerate, and alpha - (carbamylazo) - alpha, alpha1-dicyclohexylacetonitrile. Specifications 622,374, 623,472, 626,155, 631,225, 634,757, 641,679, [all in Group IV (a)], and 649,934 are referred to.